HAND JAMSpecs Material: leather, nylon lining Thickness: 1. 1 mm Weight: 46 g (1. 6 oz) pair, size M Use: Alpine big wall climbing provides protection while jamming, unobtrusive while face climbing Sizing Measure: Palm circumference just below the knuckles, hand should be relaxed. Fit: Secure when hand is closed jamming, relaxed when hand is open. Stretch: The leather will soften and mold to your hand like a new pair of climbing shoes becoming uniquely yours.